Effect of nano-MgO on basic properties and microstructures of cement-based materials

Abstract

Nano-magnesium oxide (MgO) can be used as an expansion agent for cement-based materials, but little is known about the influence of nano-magnesium oxide on the mechanics, microstructure and expansion stability of cement materials. The influence of nano-magnesium oxide on the consistency, fluidity, porosity, dry and wet densities, mechanical properties and microstructures of cement-based materials was researched in this study. The results show that the compressive strength and flexural strength of the cement mortar test block containing nano-magnesium oxide particles increase and are higher than those of the control cement mortar test block at any time. The addition of nano-magnesium oxide increases the mechanical strength of the cement mortar block, and the strengthening effects are most obvious in the early stage of maintenance. When the curing age is 28 days and the nano-magnesium oxide content is 1.5%, the compressive strength and flexural strength of the modified cement mortar test block are the best. Fourier transform infrared spectroscopy and scanning electron microscopy show that the expansion effect of nano-magnesium oxide makes the microstructure of cement-based materials denser and more uniform. This paper also discusses the influence mechanism of nano-magnesium oxide on cement-based materials, which provides a reference for the application of nano-magnesium oxide in cement-based materials.